Plumatella emarginata Allman, 1844

Lee, Sue Yeon, Yoo, Jung Sun & Kim, Seung Tae, 2017, Taxonomic study of freshwater bryozoans from Jeju Island, Korea, Journal of Species Research 6, pp. 129-134 : 130-132

2. Plumatella emarginata Allman, 1844

ṞHẍŭffinjḍNj ( Fig. 3)

Plumatella emarginata Allman, 1844: 330 ; Seo, 1998: 372-373, fig. 1; 2005: 268-269, pl. 4; 2011: 15-16, fig. 3; Wood and Okamura, 2005: 51, 80, figs. 21, 47, 48; Hirose and Mawatari, 2011a: 4-5 , fig. 2C.

Material examined. Susan reservoir, 30 Jun. 2015; Suwori pond, 4 Jul. 2015; Sasaengi pond, 28 May 2016;

Geumoreum, 29 May 2016.

Substratum. Water caltrop, plastic bag and plastic bottle.

Description. Colony variable, light brown to dark brown in color ( Fig. 3A, B). Zooid long and tubular, loosely free branching and V-shaped emargination mark. Tentacles 30-45. Floatoblasts elliptical, elongate, asymmetrical, 384.05 (369.8-398.3) μm long by 211.3 (208.5- 214.1) μm wide, length/width ratio of about 1.8; fenestra of ventral circular, 127.72 μm ( Fig. 3C): both covered with tubercles, fenestra of ventral more than four times of dorsal. Sessoblasts ( Fig. 3D) oval, flat, annulus nar- row and smooth, fenestra 104.26 (105.35-103.17) μm long by 75.98 (74.01-77.96) μm wide, length/width ratio of about 1.3, annulus 7.36 (6.47-7.45) μm, complete- ly covered with uniform tubercles, stick to substratum firmly in linear form.

Remarks. The floatoblasts had only been collected from Paldang, Daecheong and Andong reservoirs in Korea until now ( Seo, 1998; 2005). In this study, we were fortunate to collect the colony and sessoblast as well as floatoblasts, which attached to the water caltrop, plastic bag and plastic bottle.

Distribution. Korea, Japan, Europe, North America, and New Zealand.

* 3. Plumatella mukaii Wood, 2001 ŖṺffiẍŭffinjḍNj ( Fig. 4) (ljḓ)

Plumatella mukaii Wood, 2001: 51 , figs. 1, 3-6; Hirose and Mawatari, 2011a: 6-7 , fig. 2D.

Material examined. NIBRIV0000760229, Ojori pond, 8 Nov. 2015; Ojori pond, 15 Dec. 2015.

Substratum. Wood and plastic bag.

Description. Colony irregular branched, adhering to substratum, light brown to dark brown in color ( Fig. 4A). Zooid tubular and well chitinized. Floatoblasts oval, light brown to dark brown, asymmetrical, ventral strongly convex and dorsal almost flat, 236.89 (230.51- 243.28) μm long by 161.63 (150.88-172.39) μm wide, length/width ration of about 1.5. Dorsal fenestra small, oval, 80.50 μm long by 52.35 μm wide, length/width ration of about 1.5, less than half as long as ventral fenestra. ( Fig. 4B). Ventral fenestra almost circular, 127.93 (125.79-130.07) μm ( Fig. 4C). Fenestra of both dorsal and ventral covered with tubercles and wrinkled ( Fig. 4D). Annulus not smooth, covered with minute tubercles ( Fig. 4E).

Remarks. Plumatella mukaii Wood, 2001 is similar to Plumatella emarginata Allmann, 1844 in the colonial form and shape of floatoblast, but differs by having the minutely wrinkled surface of floatoblast. In addition, the floatobalsts in this study were significantly shorter than those of previous studies ( Wood, 2001; Hirose and Mawatari, 2011a). This species is reported from Korea for the first time.

Distribution. Korea, Japan, India, Thailand, Chile, and North America.

* 4. Plumatella rugosa Wood, Wood, Geimer and Massard, 1998 ŤǬ ẍŭffinjḍNj ( Fig. 4) (ljḓ)

Plumatella rugosa Wood et al., 1998: 642-643 ; Taticchi et al., 2005: 176-177, figs. 2-13; Wood and Okamura, 2005: 61, 90, fig. 32; Hirose, 2012: 21, fig. 3.

Material examined. NIBRIV0000760225, Susan reservoir, 5 Jun. 2015; Wonmul pond, 4 Jun. 2015; Bungurut pond, 4 Jul. 2015.

Substratum. Plastic bottle and styrofoam.

Description. Floatoblast oval, 316.5 (304.7-328.3) μm long by 229.15 (219.5-238.8) μm wide, with length/ width ratio of about 1.4 ( Fig. 5A). Dorsal fenestra nearly round, tubercles on reticulation, 117.65 (90.9-144.4) μm long by 133.15 (119.5-146.8) μm ( Fig. 5B). Annulus reticulation, lacking tubercles, cells concave ( Fig. 5C).

Remarks. This species is reported from Korea for the first time. Colony was not found. Floatoblast is similar to that of Plumatella repens (Linnaeus, 1758) in the shape and tubercles of fenestra, but differs in that it has reticulation without tubercles on annulus surface. Plumatella rugose is common in North America and has also been reported from New Zealand ( Wood and Okamura, 2005), Italy (Taticchi and Pieroni, 2005), and Japan. Furthermore, the floatoblast of our specimen had a length/width ratio of about 1.4, whereas the reported ratio was approximately 1.5 in Japan and 1.37± 0.01 in Italy.

Distribution. Korea, Japan, North America, New Zealand, and Italy.